1. Field of the Invention
The present invention relates to a novel gear bearing having components that perform both gear and bearing functions in a single component using two non-parallel surfaces simultaneously, including an embodiment which is designed to substantially eliminate backlash associated with all gear systems.
2. Description of the Related Art
A first known planetary gear system uses helical planetary gears with two sets of ball bearings and drives its output off a carrier. In driving off the carrier, mechanical advantage and efficiency are sacrificed. The two sets of ball bearings locate and stabilize the operation of the gears. This arrangement takes up space and the interfaces make for a weaker system. By using two, or even one separate bearing, separate interfaces require a separate attachment/detachment means which tends to rattle and is so flexible that the structure is weakened.
A second known design involves harmonic drives. Harmonic drives come in two main types, a pancake type (short axial length) and a cup type (with a larger axial length). Harmonic drives operate by means of a wave generator which rotates and, in so doing, periodically pushes a flexible spline (with teeth) radially outward in two diametrically opposite places. As the spline deflects outwards, its teeth push against the sides of the teeth of the output ring, causing the output ring to move to one side. As the wave generator turns, the points of the flexible spline turn with it, and the output ring moves with it also. There is generally one less tooth in the output ring than in the flex spline, so as the flex spline makes a complete cycle, the output ring rotates a total width of two teeth. The pancake version is not as easy to lubricate and is not as efficient as the cup type, though they are more compact. The cup type is more efficient but is not as compact. Both types are expensive and structurally weak, and the flexible splines tend to fail due to stripping.
A third known design is disclosed in U.S. Pat. No. 5,409,431, involving Carrier-Less, Anti-Backlash Planetary Drive System (Apr. 25, 1995, by John M. Vranish). While an anti-backlash feature is desirable to minimize “dead zones,” this system is unduly bulky, too complicated and very expensive to manufacture. Therefore, there remains in the prior art a need for gear bearings that exhibit a more straightforward, streamlined design, as well as an anti-backlash feature.